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Randomized, blinded clinical trial comparing immunogenicity of three different schemes of antipneumococal vaccine in HIV-infected adults: Group 1 – 23-valent polysaccharide vaccine and Group 2 – 7-valent conjugate vaccine and Group 3 - 7-valent conjugate vaccine followed to 23-valent polysaccharide vaccine 60 days after. Each group included 110 individuals. To assessment of immunogenicity, serotype-specific antipneumococcal antibodies was measured before first vaccination, day 60th (immediately before second vaccine) and day 180th. All patients were contacted between 3 to 7 days after each vaccination to evaluation of adverse event related to vaccination.

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All individuals aged 18-60 years with HIV infection documented by enzyme-linked immunosorbent assay (ELISA) and Western-Blot testing, and with T-CD4 count above 200 cells/mm3 in two different occasions in the past six months were eligible. Were included in trial individuals who demonstrated understanding and signed consent form.

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Exclusion criteria included: any acute febrile illness at the moment of vaccination, active AIDS-defining clinical condition, previous immunization with any of the pneumococcal vaccines, any systemic malignancy neoplasm, use of immunoglobulin within the last three months, current pregnancy, antecedent of allergy to any of the pneumococcal vaccine components.

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To evaluate immunogenicity, the following parameters were calculated with 95% confidence intervals (CI) for each intervention group: (a) GMCs for serotypes 6B, 9V and 14 and the percentages of individuals with serotype-specific IgG above 0.35 mcg/mL and 1.0 mcg/mL; (b) proportion of individuals with 4-fold or more increase in specific antibody concentrations for each serotype.

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At baseline there were no significant differences across the three groups in geometric medium concentrations of antipneumococcal antibodies or in the proportion of individuals with IgG antibody concentration above 0.35 mcg/mL or 1.0 mcg/mL for all serotypes analyzed. Sixty days after the initial dose, all study groups showed significant increases in geometric medium concentrations of the antipneumococcal antibodies for all serotypes. At day 180, the antibody levels decreased in all groups for all serotypes, though less markedly for serotypes 6B and 14 in recipients of a 7-valent conjugate vaccine and booster with 23-valent polysacharide (Group 3). The mean concentration of antipneumococcal antibodies and the proportion of individuals with antibody concentrations above 0.35 mcg/mL and 1.0 mcg/mL 60 days post-vaccination were similar for the three serotypes analyzed. However, the proportion of individuals who achieved at least a 4-fold increase in antibody levels was higher to serotypes 6B and 9V in patients primed with 7-valent conjugate vaccine (groups 2 and 3). At day 180, no significant differences were observed for all serotypes as to mean antibody concentrations and proportion of individuals with IgG levels above 0.35 mcg/mL or 1.0 mcg/mL, but the proportion of patients mounting antibody response of at least post- to prevaccination 4-fold increases was lower to serotypes 6B and 9V in recipients of 23-valent polysacharide alone (group 1). No statistical differences were observed after receipt of 7-valent conjugate vaccine alone (group 2) compared with a 23-valent polysacharide after 7-valent conjugate vaccine priming (group 3) in all measurement. All strategies were well tolerated. No severe local or systemic symptoms were reported.